JP4110266B2 - Copolymer, method for producing the same, and method for producing hydrogenated copolymer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an α, β-unsaturated nitrile-conjugated diene copolymer, a method for producing the same, and a method for producing a hydrogenated copolymer using the copolymer.
[0002]
[Prior art]
A method for producing a highly saturated hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer by hydrogenating a carbon-carbon double bond of an α, β-unsaturated nitrile-conjugated diene copolymer is as follows: It is known. Such hydrogenated copolymers have excellent properties such as oil resistance, weather resistance and ozone resistance, and are produced in large quantities on an industrial scale. And it is used for a wide range of applications such as automobile-related members.
[0003]
For the hydrogenation reaction of the copolymer as described above, hydrogenation catalysts containing various metals or non-metals can be used, but metals belonging to the platinum group are common, for example, ruthenium, rhodium, palladium, platinum Homogeneous or heterogeneous catalysts containing the like.
[0004]
By the way, platinum group metals such as rhodium and palladium have limited production and are rare and expensive metals. There is a demand for a reduction in the amount of catalyst used. Moreover, in the implementation of a hydrogenation reaction on an industrial scale represented by the production of a hydrogenated acrylonitrile-butadiene copolymer, it is also required to perform the reaction more efficiently.
[0005]
In order to solve such technical problems, for example, (1) Improvement of a carrier supporting a hydrogenation catalyst (Japanese Patent Laid-Open Nos. 57-205404, 58-17103, 61-247706) ), (2) a method using a homogeneous catalyst in which a hydrogenation catalyst and a specific ligand compound are combined (JP 59-115303 A, JP 3252405 A), (3) A method of combining a specific metal compound (Japanese Patent Laid-Open No. 2-196803), (4) a method of using a polymer complex comprising a hydrogenation catalyst and a specific polymer (Japanese Patent Laid-Open No. 6-298844), and the like. Many proposals have been made regarding reduction in use and high activation.
[0006]
These improved methods show some effects for reducing the amount of catalyst containing platinum group metals and increasing the efficiency of the hydrogenation reaction, but it is still difficult to say that they are sufficiently satisfactory. Further improvements are needed.
[0007]
[Problems to be solved by the invention]
In view of the above circumstances, an object of the present invention is to provide an α, β-unsaturated nitrile-conjugated diene copolymer suitable as a raw material for producing a hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer and a simple production thereof. It is to provide a method.
Another object of the present invention is to provide a method for industrially advantageously producing a hydrogenated copolymer using such an α, β-unsaturated nitrile-conjugated diene copolymer as a production raw material. There is also.
[0008]
[Means for Solving the Problems]
The inventors focused on the point that the α, β-unsaturated nitrile-conjugated diene copolymer is subjected to a hydrogenation reaction in the form of a solution, and the properties and catalytic activity of the copolymer solution We have been intensively studying the relationship. As a result, it has been found that if a copolymer capable of setting the pH of the copolymer solution in a specific region is used, the hydrogenation reaction proceeds very rapidly and the target hydrogenated copolymer can be produced efficiently.
[0009]
In addition, by improving the conventional production method of this kind of α, β-unsaturated nitrile-conjugated diene copolymer, crumb obtained by coagulating the copolymer produced in the polymerization step, and basic By newly providing a step of bringing the aqueous solution into contact with the aqueous solution, it was found that a copolymer capable of bringing the pH of the copolymer solution into a specific region as described above could be reliably and easily produced, thereby completing the present invention. It was.
[0010]
Thus, according to the first invention of the present invention, the pH of the α, β-unsaturated nitrile-conjugated diene copolymer, measured by dissolving in tetrahydrofuran, is more than 7. A featured copolymer is provided.
[0011]
According to the second invention of the present invention, the step (A) of copolymerizing an α, β-unsaturated nitrile monomer and a conjugated diene monomer; and the copolymer produced in the step (A) There is provided a method for producing a copolymer according to the first invention, which comprises a step (B) of bringing crumb obtained by coagulation into contact with a basic aqueous solution.
[0012]
Furthermore, according to the third invention of the present invention, there is provided a method for producing a hydrogenated copolymer, characterized in that the copolymer according to the first invention is hydrogenated in the presence of a hydrogenation catalyst. .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the copolymer of the present invention, a method for producing the copolymer, and a method for producing the hydrogenated copolymer will be described in detail.
[0014]
(Copolymer)
The copolymer of the present invention is an α, β-unsaturated nitrile-conjugated diene copolymer, and has an essential characteristic that the pH of the copolymer solution measured by dissolving in tetrahydrofuran is more than 7. To do. The present copolymer is particularly useful as a raw material for producing a hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer.
[0015]
Here, “the pH of the copolymer solution measured by dissolving in tetrahydrofuran” refers to 6 g of α, β-unsaturated nitrile-conjugated diene copolymer dissolved in 100 g of tetrahydrofuran (hereinafter also referred to as THF). A solution is prepared, 2 ml of distilled water is added while stirring the solution, and the pH is measured using a pH meter after 2 minutes.
[0016]
“Α, β-unsaturated nitrile-conjugated diene copolymer” means an α, β-unsaturated nitrile monomer having a polymerizable unsaturated bond at the α, β-position of the nitrile group, and a conjugated diene monomer. In addition to these two types of monomers, a copolymer obtained by copolymerizing another type of copolymerizable monomer is also included.
[0017]
The α, β-unsaturated nitrile-conjugated diene copolymer of the present invention is not particularly limited, and examples thereof include acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-butadiene-isoprene copolymer, and methacrylonitrile. -Butadiene copolymer, methacrylonitrile-isoprene copolymer, methacrylonitrile-butadiene-isoprene copolymer, acrylonitrile-methacrylonitrile-butadiene copolymer, acrylonitrile-butadiene-methyl acrylate copolymer, acrylonitrile-butadiene-acrylic An acid copolymer etc. are mentioned.
[0018]
Among the above copolymers, acrylonitrile-butadiene copolymer and methacrylonitrile-butadiene copolymer are preferable from the viewpoint of practicality and versatility as a raw material for producing a hydrogenated copolymer, and butadiene-acrylonitrile copolymer. Is more preferable.
[0019]
Although the monomer composition ratio in such a copolymer is not particularly limited, it is 5 to 95% by weight of a conjugated diene monomer and 95 to 5% by weight of an α, β-unsaturated nitrile monomer, preferably a conjugated diene monomer. 10 to 90% by weight of the monomer and 90 to 10% by weight of the α, β-unsaturated nitrile monomer. The composition ratio of another monomer copolymerizable with the conjugated diene monomer and the α, β-unsaturated nitrile monomer is usually 0 to 50% by weight based on the total of the former two. Further, the weight average molecular weight (gel permeation chromatography method, standard polystyrene conversion) of the copolymer is not particularly limited, but is usually 5,000 to 500,000.
[0020]
The copolymer of the present invention is not particularly limited as long as the pH of the copolymer solution measured by dissolving in THF is more than 7, but preferably 7.2 to 12, more preferably 7.5 to 11.5. Most preferably, it is in the range of 8-11. When a copolymer having a pH of 7 or less is used as a raw material for producing a hydrogenated copolymer, the reaction proceeds slowly even if a large amount of hydrogenation catalyst is used, and the object of the present invention is achieved. It is difficult.
[0021]
The method for preparing the copolymer of the present invention is not particularly limited. For example, the copolymer and the basic aqueous solution formed at an appropriate site located after the polymerization step of a known production flow for obtaining this type of copolymer. There is a method of newly providing a processing step of contacting the. More preferably, it can be reliably and easily produced by the method for producing a copolymer of the present invention described below.
[0022]
(Method for producing copolymer)
The production method of the present invention is obtained by coagulating an α, β-unsaturated nitrile monomer and a conjugated diene monomer (A); and the copolymer produced in the step (A). A step (B) of bringing crumb into contact with a basic aqueous solution. Although it is essential that the method includes the steps (A) and (B), the method may include other additional steps usually performed to obtain this type of polymer.
[0023]
The α, β-unsaturated nitrile monomer used in the step (A) is not particularly limited, and examples thereof include acrylonitrile, methacrylonitrile, crotonnitrile, and vinylidene cyanide. Among these, acrylonitrile is preferable. The α, β-unsaturated nitrile monomers may be used alone or in combination of two or more.
[0024]
The conjugated diene monomer is not particularly limited as long as it is a polymerizable monomer having a conjugated diene structure. For example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2 , 3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene and the like. Among these, 1,3-butadiene and 2-methyl-1,3-butadiene are preferable, and 1,3-butadiene is more preferable. The conjugated diene monomers may be used alone or in combination of two or more.
[0025]
In the step (A), not only the above α, β-unsaturated nitrile monomer and conjugated diene monomer, but also other types of monomers copolymerizable therewith can be used in combination. Examples of such another type of monomer include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid and itaconic acid; methyl acrylate, n-butyl acrylate, 2 Α, β-unsaturated carboxylic acid esters such as ethylhexyl acrylate, methyl methacrylate and methyl crotonate; α, β-unsaturated carboxylic acid amides such as acrylamide and methacrylamide; styrene, α-methylstyrene, p-methylstyrene Vinyl aromatic compounds such as vinyl acetate and vinyl pyridine; vinyl alcohol esters such as vinyl acetate and vinyl propionate; vinyl ether compounds such as fluoroethyl vinyl ether; and the like.
[0026]
Among these different types of monomers, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester are preferably used. Different types of monomers may be used alone or in combination of two or more.
[0027]
A conventionally known emulsion polymerization method, solution polymerization method or bulk polymerization method can be employed as a method for copolymerizing the monomers as described above. An emulsion polymerization method or a solution polymerization method is preferable, and an emulsion polymerization method is more preferable.
[0028]
Emulsion polymerization is generally performed in an aqueous medium using a radical polymerization initiator, an emulsifier, a molecular weight regulator and the like. The emulsion polymerization may be any of batch, semi-batch and continuous, and the polymerization temperature and pressure are not limited and can be carried out under known conditions.
[0029]
Examples of the radical polymerization initiator include hydroperoxides such as benzoyl peroxide, t-butyl-hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide; azobisisobutyronitrile, 2,2′-azobis Aliphatic azo compounds such as (2,4-dimethylvaleronitrile);
[0030]
Examples of the emulsifier include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant, and an anionic surfactant is preferable. These emulsifiers may be used alone or in combination of two or more. The amount used is not particularly limited.
[0031]
Examples of molecular weight regulators include molecular weight regulators having mercapto groups such as t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan; alkyl halides such as dichloromethane, dibromomethane, carbon tetrachloride; methanol, ethanol, etc. Alcohols; α-methylstyrene dimers; and the like. Among these, a molecular weight regulator having a mercapto group is preferable. The molecular weight regulators may be used alone or in combination of two or more. The amount used may be appropriately determined according to the molecular weight of the target polymer.
[0032]
The copolymerization reaction in the step (A) is usually stopped using a known polymerization stopper. The polymerization conversion rate is not particularly limited, and can be arbitrarily adjusted and appropriately determined. From the viewpoint of efficiently producing the raw material polymer, the polymerization conversion rate is preferably high, and is usually 70% or more, and preferably 80% or more.
[0033]
In the system after completion of the copolymerization in the step (A), unreacted monomers such as conjugated diene monomer and α, β-unsaturated nitrile monomer remain. It is preferable to remove the monomer out of the system. The unreacted monomer removed to the outside of the system can be purified and used again in the step (A).
[0034]
Step (B) is a step performed subsequent to step (A), and it is essential to contact the crumb obtained by coagulating the copolymer produced in step (A) with a basic aqueous solution. .
[0035]
The copolymer produced in the step (A) is usually in a latex state and can be coagulated by a known method to obtain crumb. As a coagulation method, for example, a copolymer latex or a coagulant is continuously and / or sequentially supplied to a coagulation tank, and a coagulation slurry (a mixture of crumb and serum water) is discharged continuously and / or sequentially. A continuous system; a batch system in which a polymer latex or a coagulant is supplied to a coagulation tank and stirred for a certain time, and then the coagulated slurry is discharged;
[0036]
As the coagulant, those generally used for coagulation of latex can be used. Examples thereof include inorganic acids such as hydrochloric acid and sulfuric acid; organic acids such as acetic acid and formic acid; inorganic acids or metal salts of organic acids; It is done. Examples of the metal salt include sodium chloride, calcium chloride, aluminum chloride, aluminum sulfate, magnesium sulfate, and aluminum sulfate, magnesium sulfate, and calcium chloride are preferable. Such metal salts are usually used as aqueous solutions. Moreover, water-soluble polymer compounds, such as a polyethylene oxide and polyvinyl alcohol, can also be used together as a coagulation aid.
[0037]
Two or more coagulation tanks can be continuously provided as necessary. The shape of the coagulation tank is not particularly limited, and examples thereof include a sealed tank and an open tank. The concentration of crumb in the coagulation tank is preferably 3 to 60% by weight, more preferably 5 to 50% by weight, and particularly preferably 6 to 40% by weight.
[0038]
In order to efficiently bring the crumb into contact with the basic aqueous solution, the shape of the crumb is preferably smaller and more porous. The particle size (maximum length) of the crumb is preferably 5 mm or less, more preferably 3 mm or less. The particle size of the crumb can be adjusted by appropriately selecting the coagulation conditions such as the type and amount of the coagulant and the coagulation treatment temperature. The amount of the coagulant used is usually 1 to 100% by weight, preferably 2 to 50% by weight, based on the copolymer produced in the step (A). The coagulation treatment temperature is usually 5 to 80 ° C, preferably 10 to 60 ° C.
[0039]
Thus, the slurry containing the crumb obtained by coagulation is transferred to a treatment tank (hereinafter referred to as a base treatment tank) for bringing the crumb into contact with the basic aqueous solution. In order to prevent the basic aqueous solution from being diluted or neutralized with the serum water contained in the slurry, it is preferable to drain water during the transfer of the slurry to remove a part of the serum water. Moreover, you may provide the 1 or more water-washing tank which wash | cleans a crumb between a coagulation tank and a base treatment tank. In addition, after depositing crumbs in the coagulation tank, an amount of a basic compound or an aqueous solution thereof that makes the slurry basic can be added to the coagulation tank. In this case, the coagulation tank also serves as a base treatment tank.
[0040]
The pH of the basic aqueous solution to be contacted with crumb is usually 8 to 13.5, preferably 9 to 13, and more preferably 10 to 12.5. In order to prevent the pH of the basic aqueous solution from fluctuating in the slurry flowing from the coagulation tank or the washing tank provided as necessary, the pH in the basic treatment tank is always measured, and the basic aqueous solution provided separately. It is preferable to appropriately replenish the basic aqueous solution from the storage tank to the base treatment tank.
[0041]
Contact between the crumb and the basic aqueous solution may be a batch type or a continuous type, and can be selected according to the amount of treatment. The contact time in the case of continuous contact, that is, the average residence time obtained by dividing the liquid part volume of the base treatment tank by the inflow amount per hour of the inflowing slurry is usually 5 minutes to 10 hours, preferably 10 minutes. ~ 5 hours. In order to prevent a short circuit of the inflowing slurry in the base treatment tank, it is preferable to provide a stirring device in the base treatment tank. The contact temperature (temperature of the basic aqueous solution at the time of contact) is usually 10 to 80 ° C., preferably 20 to 70 ° C.
[0042]
The basic aqueous solution is prepared by dissolving a known inorganic and / or organic basic compound in water. Preferably, it is an aqueous solution of an inorganic basic compound such as an alkali metal compound or an alkaline earth metal compound.
[0043]
Examples of the alkali metal compound include hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; carbonate compounds such as lithium carbonate, sodium carbonate and potassium carbonate; lithium hydrogen carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate Hydrogen carbonate compounds such as: oxides such as lithium oxide, potassium oxide and sodium oxide; fatty acid salt compounds such as potassium acetate and sodium acetate; lithium methoxide, lithium ethoxide, sodium methoxide, sodium ethoxide, potassium-t -Alkoxides such as butoxide; Phenoxides such as sodium phenoxide and potassium phenoxide; Preferred are alkali metal hydroxides, carbonate compounds, and bicarbonate compounds, and more preferred are hydroxides.
[0044]
Examples of alkaline earth metal compounds include hydroxides, carbonate compounds, hydrogen carbonate compounds, oxides, fatty acid salt compounds, alkoxides, phenoxides, and the like of alkaline earth metals such as magnesium, calcium, strontium, and barium. Can be mentioned. Alkali earth metal hydroxides, carbonate compounds and bicarbonate compounds are preferred, and hydroxides are more preferred.
[0045]
A basic compound may be used independently or may use 2 or more types together. The aqueous solution concentration of the basic compound is not particularly limited, and is usually 0.5 to 10% by weight, preferably 1 to 5% by weight.
[0046]
The crumb thus brought into contact with the basic aqueous solution is recovered by draining after passing through a water washing tank provided at the subsequent stage of the base treatment tank as necessary. Then, it spin-dry | dehydrates with a centrifugal dehydrator or a squeezer, and it dries with a band dryer, a flash dryer, an extrusion dryer, etc.
[0047]
The α, β-unsaturated nitrile-conjugated diene copolymer obtained by the method for producing a copolymer of the present invention has a pH of the copolymer solution measured by dissolving in THF of more than 7, It is suitable as a raw material for producing an α, β-unsaturated nitrile-conjugated diene copolymer.
[0048]
(Method for producing hydrogenated copolymer)
The method for producing a hydrogenated copolymer of the present invention comprises an α, β-unsaturated nitrile-conjugated diene copolymer (hereinafter referred to as raw material weight) in which the pH of the copolymer solution measured by dissolving in THF is more than 7. Characterized in that it is hydrogenated in the presence of a hydrogenation catalyst.
[0049]
The hydrogenation catalyst is not particularly limited, but usually a metal belonging to Group VIII of the periodic table or a metal compound thereof is used. Of the elements belonging to Group VIII of the periodic table, platinum group elements such as ruthenium, rhodium, palladium, osmium, iridium and platinum are preferred. Among these, palladium and rhodium are more preferable, and palladium is particularly preferable. A hydrogenation catalyst may use together 2 or more types selected from the metal and metal compound which belong to periodic table group VIII. In this case, it is preferable to use palladium as the main active ingredient.
[0050]
The hydrogenation catalyst is usually supported on a known catalyst carrier such as activated carbon, activated clay, alumina gel, silica gel, diatomaceous earth and used as a supported catalyst. In this case, the supported amount of the catalytic metal component is usually 0.5 to 80% by weight, preferably 1 to 50% by weight, more preferably 2 to 30% by weight based on the support. Further, it can be used as an unsupported catalyst without being supported on a carrier.
[0051]
The catalyst metal component may be supported on the carrier according to a known method, and examples thereof include an impregnation method, a coating method, a spray method, an adsorption method, and a precipitation method. After the catalytic metal component is supported on a carrier, it can be formed into an appropriate shape, for example, a spherical shape, a cylindrical shape, a polygonal column shape, a honeycomb shape, etc. .
[0052]
When a palladium-based catalyst (palladium and / or palladium compound) is used as the hydrogenation catalyst, a II-valent or IV-valent compound is usually used as the palladium compound. The form may be any of salts, complex salts and complexes, for example, organic acid salts such as palladium acetate and paracyanide cyanide; halides such as palladium fluoride, palladium chloride, palladium bromide and palladium iodide; nitric acid Oxyacid salts such as palladium and palladium sulfate; palladium oxide; palladium hydroxide;
[0053]
Dichlorocyclooctadiene palladium, dichloronorbornadiene palladium, tetrakis acetonitrile palladium tetrafluoroborate, tetrakisbenzonitrile palladium ditetrafluoroborate, dichlorobisacetonitrile palladium, dichlorobisethylenediamine palladium, bisacetylacetonato palladium, tristriphenylphosphine acetonitrile palladium tetra Complex salts or complexes of fluoroborate, dichlorobistriethylphosphine palladium, dichlorobis (dimethylsulfide) palladium, dibenzoylsulfide palladium, bis (2,2'-bipyridine) palladium perchlorate, tetrakis (pyridine) palladium dichloride, etc. It is done.
[0054]
These palladium compounds can be used by obtaining commercial products. Moreover, what was prepared according to the method described in "New Experimental Chemistry Course" Volumes 8 and 12 (published in Maruzen 1976) and "Chemistry and Application of Precious Metals" (published by Kodansha Scientific 1984) can also be used.
[0055]
When a rhodium catalyst (rhodium and / or rhodium compound) is used as the hydrogenation catalyst, examples of the rhodium compound include halides such as rhodium chloride, rhodium bromide and rhodium iodide; rhodium nitrate, rhodium sulfate and the like. Inorganic acid salts; organic acid salts such as rhodium acetate, rhodium formate, rhodium propionate, rhodium butyrate, rhodium valerate, rhodium naphthenate; rhodium oxide; rhodium trihydroxide;
[0056]
Dichlorobis- (triphenylphosphine) rhodium, trichlorotris-pyridinerhodium, tetrarhodium dodecacarbonyl, dirhodium octacarbonyl, hexarhodium hexadecarbonyl, rhodium dicarbonylacetylacetonate, rhodiumcarbonyl (1-phenylbutane-1,3-dione ), Tris (hexane-2,4-dione) rhodium, tris (heptane-2,4-dione) rhodium, tris (1-phenyl-butane-1,3-dione) rhodium, tris (3-methyl-pentane-) And complex compounds such as 2,4-dione) rhodium and tris (1-cyclohexylbutane-1,3-dione) rhodium.
[0057]
In the method for producing a hydrogenated copolymer of the present invention, the raw polymer is hydrogenated in a state dissolved in a solvent. The solvent is not particularly limited as long as it does not adversely affect the hydrogenation catalyst and dissolves the raw polymer. The density | concentration of a raw material polymer is 1 to 70 weight% normally with respect to the whole quantity of a solution, Preferably it is 2 to 40 weight%.
[0058]
Examples of the solvent for dissolving the raw material polymer include linear or cyclic aliphatic hydrocarbons such as n-hexane, cyclohexane and n-heptane; aromatic hydrocarbons such as benzene, toluene, xylene and chlorobencene; acetone, Ketones such as methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone; ethers such as diethyl ether, tetrahydrofuran, dioxane, anisole; esters such as ethyl acetate; It is done. Of these solvents, ketones are preferably used.
[0059]
The reaction temperature of hydrogenation is usually 0 ° C to 200 ° C, preferably 5 ° C to 150 ° C, more preferably 10 to 100 ° C. An excessively high reaction temperature is undesirable because side reactions such as hydrogenation of nitrile groups occur and the reaction solvent is hydrogenated. On the other hand, when the reaction temperature is excessively lowered, the reaction rate is lowered, which is not practical.
[0060]
The pressure of hydrogen is usually atmospheric pressure to 20 MPa, preferably atmospheric pressure to 15 MPa, more preferably atmospheric pressure to 10 MPa. Although reaction time is not specifically limited, Usually, it is 30 minutes-50 hours.
[0061]
After completion of the hydrogenation reaction, the catalyst can be removed or recovered from the reaction solution by using a normal catalyst removal method such as a filtration method, an adsorption method, or a centrifugal separation method. The catalyst recovered in this way can be used again in the hydrogenation reaction as it is or after being subjected to a regeneration treatment as necessary. Further, the catalyst can be left as it is in the hydrogenated copolymer without removing the catalyst.
[0062]
The method for recovering (separating) the hydrogenated copolymer from the hydrogenation reaction mixture is not particularly limited, and a method generally used industrially may be appropriately employed. For example, a steam coagulation method in which the reaction mixture is brought into direct contact with water vapor; a method in which the reaction mixture is dropped on a heated rotating drum to evaporate the solvent; a direct drying method in which the solvent in the reaction mixture is evaporated under reduced pressure; a poor reaction mixture And a method of precipitating the hydrogenated copolymer by adding a solvent. The hydrogenated polymer thus separated is further recovered as a solid hydrogenated polymer through a drying process such as hot air drying, reduced pressure drying or extrusion drying.
[0063]
The hydrogenation rate of the hydrogenated copolymer obtained by this method (the ratio of hydrogenated carbon-carbon double bonds to the total number of carbon-carbon double bonds present in the raw polymer) By appropriately changing the reaction conditions, it can be arbitrarily controlled within the range of 1 to 100%. The hydrogenation rate represented by the iodine value is preferably 120 or less. Such a hydrogenated copolymer is excellent in various properties such as weather resistance, ozone resistance, heat resistance and cold resistance, and can be used for a wide range of industrial applications.
[0064]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. Further, parts and% in these examples are based on weight unless otherwise specified.
[0065]
The pH of the obtained copolymer (raw polymer a to c) in tetrahydrofuran solution was prepared by dissolving 6 g of copolymer in 100 g of tetrahydrofuran and adding 2 ml of distilled water while stirring this solution. Then, after 2 minutes, it was measured at room temperature using a pH meter.
[0066]
(Example 1) Production of raw material polymer a
In the autoclave, 180 parts of ion-exchanged water, 2 parts of potassium oleate, 37 parts of acrylonitrile and 0.5 part of t-dodecyl mercaptan (molecular weight regulator) were sequentially added to replace the inside of the reactor with nitrogen. Next, 63 parts of butadiene was sealed, the reactor was cooled to 5 ° C., and 0.1 part of paramentane hydroperoxide (polymerization catalyst) and 0.05 part of ferrous sulfate were added. The contents were mixed well by rotating the reactor at 5 ° C. for 16 hours. Thereafter, an aqueous hydroquinone solution having a concentration of 10% by weight was added to the reactor to terminate the polymerization. The polymerization conversion was 90%. The reaction mixture obtained by removing unreacted monomers was added to water in which 3 parts of aluminum sulfate heptahydrate had been dissolved with stirring to precipitate a polymer crumb. After separating the polymer crumb, it was put into 1000 parts of a potassium hydroxide aqueous solution having a pH of 11.5 and stirred at 40 ° C. for 45 minutes to bring the polymer crumb into contact with the potassium hydroxide aqueous solution well. After fractionating the polymer crumb, it was put into 1000 parts by weight of water and washed with stirring for 10 minutes. The polymer crumb was fractionated and dried overnight in a vacuum dryer. The tetrahydrofuran solution of this raw material polymer (acrylonitrile-butadiene copolymer) a had a pH of 9.3.
[0067]
(Example 2) Production of raw material polymer b
A reaction mixture was obtained in the same manner as in Example 1. The reaction mixture was added with stirring to water in which 3 parts of aluminum sulfate heptahydrate had been dissolved. A potassium hydroxide aqueous solution was added thereto to precipitate a polymer crumb while maintaining the pH at 11.5. The polymer crumb was fractionated and charged into 1000 parts by weight of water and washed with stirring for 10 minutes. The polymer crumb was fractionated and dried overnight in a vacuum dryer. The pH of the tetrahydrofuran solution of this raw material polymer b was 9.0.
[0068]
(Comparative Example 1) Production of raw material polymer c
A polymer c was obtained in the same manner as in Example 1 except that the contact treatment between the polymer crumb and the potassium hydroxide aqueous solution performed in Example 1 was omitted. The pH of the tetrahydrofuran solution of this raw material polymer c was 7.0.
[0069]
(Example 3) Production of hydrogenated copolymer
The raw material polymer a obtained in Example 1 was dissolved in acetone to prepare a 15% solution of the raw material polymer used for the hydrogenation reaction. The autoclave was charged with 60 parts of the solution, and 0.45 part of a hydrogenation catalyst (palladium supported amount 2%) supporting palladium on magnesium silicate was added. The reactor was first purged with nitrogen and further purged twice with hydrogen, and then reacted at a hydrogen pressure of 5 MPa and 50 ° C. for 6 hours. After completion of the hydrogenation reaction, the reaction solution was concentrated under reduced pressure using a rotary evaporator to obtain a hydrogenated acrylonitrile-butadiene copolymer. As a result of measuring the hydrogenation rate of the obtained hydrogenated polymer by proton NMR, the hydrogenation rate was 93.3%.
[0070]
(Example 4) Production of hydrogenated copolymer
A hydrogenated acrylonitrile-butadiene copolymer was obtained in the same manner as in Example 3 except that the polymer b obtained in Example 2 was used. As a result of measuring the hydrogenation rate of the obtained hydrogenated polymer by proton NMR, the hydrogenation rate was 91.2%.
[0071]
(Comparative Example 2) Production of hydrogenated polymer
A hydrogenated acrylonitrile-butadiene copolymer was obtained in the same manner as in Example 3 except that the polymer c obtained in Comparative Example 1 was used. As a result of measuring the hydrogenation rate of the obtained hydrogenated polymer by proton NMR, the hydrogenation rate was 70.8%.
[0072]
As is clear from the above Examples and Comparative Examples, in the process of preparing the raw material polymer, depending on the presence or absence of the treatment (operation) for bringing the polymer crumb into contact with the basic compound (basic aqueous solution), the hydrogenation reaction The efficiency was very different. The raw material polymers a and b having a pH of more than 7 in the polymer solution measured by dissolving in tetrahydrofuran proceeded more efficiently than the raw material polymer c having a pH of 7.
[0073]
【The invention's effect】
When the α, β-unsaturated nitrile-conjugated diene copolymer of the present invention is used as a raw material for producing a hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer, the hydrogenation reaction proceeds rapidly. The target hydrogenated copolymer can be produced efficiently and advantageously industrially.

Claims (5)

alpha, beta-unsaturated nitrile - consists conjugated diene copolymer, and wherein the pH of the copolymer solution to be measured was dissolved in tetrahydrofuran is greater than 7, hydrogenated alpha, beta-unsaturated nitrile -Raw material for producing conjugated diene copolymer. The raw material for producing a hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer according to claim 1, wherein the pH of the copolymer solution measured by dissolving in tetrahydrofuran is 8-11. a step (A) of copolymerizing an α, β-unsaturated nitrile monomer and a conjugated diene monomer; and a crumb obtained by coagulating the copolymer produced in the step (A) and a basic aqueous solution. The method for producing a raw material for producing a hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer according to claim 1 or 2, characterized by comprising a step (B) of contacting. 3. Production of a hydrogenated copolymer , wherein the raw material for producing the hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer according to claim 1 or 2 is hydrogenated in the presence of a hydrogenation catalyst. Method. A hydrogenation copolymer, characterized in that a hydrogenated α, β-unsaturated nitrile-conjugated diene copolymer production raw material obtained by the production method according to claim 3 is hydrogenated in the presence of a hydrogenation catalyst. A method for producing a polymer.